The present invention relates to a transfer gear assembly for a transmission in which a needle roller thrust bearing and tapered roller bearing are preloaded against each other as they support a transfer gear.
Vehicle transmissions with multiple axles include a transfer gear to transmit torque and speed from one axis to another. These transfer gears are typically supported by multiple bearings, each having races, so that the bearings can handle significant radial as well as fore-and-aft loads originating from the helical gears. The bearing preloaded positions are held either by a large nut or a tapered snap ring.
It is desirable to improve upon the above-described transfer gear arrangement by reducing part count, reducing space usage, improving serviceability and reducing allowable axial play for the transfer gear.
The present invention provides a transfer gear assembly in which the transfer gear is supported directly by a thrust bearing and tapered roller bearing, and a preload is applied to the bearings by a tapered snap ring on a stationary hub.
More specifically, the present invention provides a transfer gear assembly for a transmission including a stationary hub having a cylindrical hub surface and a radial hub surface. The cylindrical hub surface has a circumferential groove formed therein. A tapered inner race is positioned on the cylindrical hub surface. A complement of tapered rollers is positioned on the tapered inner race. A radially extending race is positioned against the radial hub surface. A thrust bearing is positioned against the radially extending race. A transfer gear is positioned around the hub and in direct contact with the tapered roller bearing and with the thrust bearing. A tapered snap ring is positioned in the circumferential groove in contact with the tapered inner race to provide a preload on the tapered roller bearing and thrust bearing. The tapered snap ring may be replaced by a different preload member, such as a nut.
The invention also provides a method of assembling a transfer gear assembly as described above wherein the tapered inner race, tapered rollers, radially extending race, thrust bearing and transfer gear are positioned around the hub and preloaded so that the tapered snap ring drops into the circumferential groove in the hub.
Accordingly, an object of the invention is to provide a transfer gear assembly which reduces space usage, reduces part count and improves serviceabilty.
The above object and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings.